| 摘要 |
<P>PROBLEM TO BE SOLVED: To avoid deterioration of exhaust emission properties by accurately predicting NO<SB>x</SB>desorption in an NO<SB>x</SB>trap catalyst during a rich spike control, and by appropriately controlling the supply quantity of a reducing agent used at desorption of NO<SB>x</SB>. <P>SOLUTION: During a period of time the reducing agent controls the desorption of NO<SB>x</SB>and an NO<SB>x</SB>desorption speed (NO<SB>x</SB>desorption quantity) is substantially fixed, immediately after the rich spike control, exhaust emission λ is fixed at a predetermined value and supply of the reduction agent is controlled. During the following time period, when adsorption/desorption of NO<SB>x</SB>is controlled according to Langmuir adsorption equation and the NO<SB>x</SB>desorption speed is reduced, emission λ is made variable, according to the NO<SB>x</SB>desorption rate and supply of the reduction agent is controlled. <P>COPYRIGHT: (C)2009,JPO&INPIT |
